[PATCH v3] Fix problem with imx_ddrc_sdram_size calc

[Joacim Zetterling]

On Fri, Nov 05, 2021 at 10:39:27AM +0100, Sascha Hauer wrote:
> Hi Joacim,
> 
> On Mon, Nov 01, 2021 at 01:11:09PM +0100, Joacim Zetterling wrote:
> > There was some issues with the imx_ddrc_sdram_size calculation.
> > 
> > If we compare the imx8mn DDR4 evk against the LPDDR4 variant in
> > code and in the datasheets, we see the following:
> > 
> >              DDR4   LPDDR4
> >   ========================
> >   Bus width   16      16
> >   Rank        1       1
> >   Ranks       1       1
> >   Banks       4       8
> >   Banks grps  2       1
> >   Rows        17      15
> >   Col         10      10
> > 
> > This gives us the following problems:
> > 
> > 1. Bus width problem.
> >    Does not support 16 bit SDRAM bus mode, only 32 bit supported
> > 
> > 2. Row size problem.
> >    Only up to 16 bit row size support.
> > 
> > 3. Bank groups support.
> >    Only support of 1 bank group.
> > 
> > 4. Bit count problem.
> >    The imx_ddrc_count_bits function does not do a correct count.
> 
> Could you split this into four patches fixing one problem at a time?
> I am not sure the problems can be separated from each other entirely,
> but splitting this up would make it much easier to understand the
> problems and also their fixes. We'll be glad having smaller patches
> should we ever have to look at this again.
> 
> Sascha
I agree with You that the problems can not be separated completely.
But I will try to do my best. Do You prefer a patch set or separately
patches or a combination of them both?
> 
> 
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